Wouldn't it be nice to walk into a job (new or old) where the cable was already installed? Most large corporate or industrial buildings have the cable you need in place. I am speaking about Category 3 (Cat3) cabling. Telephone lines ... dead pairs ... unused pairs of wire that were installed with the building or the first phone systems. They run all over the place. Cat3 is a lower grade cable than Cat5, but it works on the same principals. It has fewer twists per inch and less quality. The maximum transmission rate is 15 megabits with a sixty percent load at 3,000 feet. That calculates out to roughly 8 megabits of transmission capability for video. Figuring at an average of 1 meg per converted analog camera and up to 1.75 meg per mega-pixel camera, you should be able to get away with four to eight cameras on a single pair. If you want to see twisted pair technology, then you can look up NVT. They do it very well. This is not to say that they are the only ones. Please don't take this as a political push. NVT comes to mind ... plus they've been doing twisted pair from the beginning. As a last note on Cat3, you can convert it to a simple network. Granted, not the biggest thing in the world, but look at the potentials.
Next on the list is Category 5 (Cat5) cabling. This is essentially Cat3 with more twists per inch, higher quality and a 100 megabit transmission rate with a 60% load. This leaves you about 60 megabits of usable carrier over 300 feet. This is or has become a very popular method of transmission and is fast intruding on Coaxial cable. However, you will not walk into the lost and forgotten telephone closets and find it installed in most buildings. You will need to install it yourself or jump onto the existing LAN. Cat5 is 10 times easier and more reliable than coaxial cable.
Next, fiber optics. I know, you think that I said I wouldn't write about fiber. I only said I wouldn't get all mushy and into a big discord. As it is, single mode fiber can be converted into a 1 gigabyte network. Using a 60 percent load factor, this means that you have the potential for about 600 megs of bandwidth to work with. The best part is that you can go up to 40 miles with an off the shelf system. That's all I'm saying now.
Wireless systems are becoming very popular. For general purposes, you can use public bands with no licensing or related issues. The key is to watch for potential interferences. It is possible for cell phones to be interfered with if you overpower an area. Equally, it is possible that your neighbor may install something that is wireless that interferes with your system or visa versa. Most wireless systems don't have a very good penetration capability and therefore get bogged down when going from floor to floor. Equally, if your wireless system doesn't have a good filtering system and advanced digital formatting, it is possible for echoes to cause you all sorts of problems.
For long shots outside, you can go into the real of using licensed bands. This is becoming very popular in many cities across the world. It allows you to set up master LAN systems that are able to be used by a multiple of groups for multiple purposes. Wireless opens up "Plug and Play" attitude. Find me a place to plug in my power (or a solar panel) and I have video on any PC, Laptop, or appropriate PDA with wireless capability. Wireless, for the most part is restricted to a 54 meg bandwidth with a 40 percent load factor. This leaves you with about 20 meg to work with, which is a very nice amount in most applications. Just figure an average of 1 meg or so per channel for video.
That takes up my space for this column. Next time we will look at the wide world of telephone lines and networks. We'll be asking what DSL lines are and they differ from T1 or T3 lines. It's really not that bad, but it helps to be able to speak with a bit of intelligence when you're thinking about uploading and downloading your systems. I'll see you in a couple of weeks. Meanwhile, you can find the voluminous writings I've done on these topics in my books and other stuff; just click over to www.ltctrainingcntr.com.
A PERSONAL REQUEST FOR HELP TO THE INDUSTRY
For the past 31 years, I have been bragging to friends and family about the security industry and it gifts to the general public. So I am now addressing that same industry, personally with a request for help.
In about six weeks, a small Catholic School on the lower west end of Davenport Iowa will be permanently closing its doors. Sadly, this is happening after 100 years of dedicated service to the education of children of all faiths. This is a school where my wife and her brothers, my three sons and a countless number of other folks that are close to me, have attended. This is a school where the teachers and staff have worked for below average wages and given from their hearts for as many as 25 years. Because we are a small parish and an equally small community, our staff was never afforded compensation or retirement benefits. They will be saying goodbye with nothing more in their pockets other than the fond memories and broken hearts that years educating others will create.